OLED devices can serve as displays for various types of consumer electronic products, such as automobile stereo displays, cellular phones, cellular smart phones, personal organizers, pagers, advertising panels, touch screen displays, teleconferencing and multimedia products, virtual reality products and display kiosks. Referring to FIG. 1, a conventional OLED device 100 is shown. The OLED device comprises a functional stack formed on a substrate 101. The functional stack comprises one or more organic functional layers 102 between a transparent first conductive layer 104 (e.g., indium tin oxide or ITO) and a second conductive layer 106. The conductive layers serve as electrodes. OLED cells are located in the active region where the cathodes and anodes overlap. A cap 160 may be provided to hermetically seal the active components. A contact layer 150 can be formed over the first conductive layer, the contact layer extending to the exterior of the encapsulation for providing external bond pads 151. Charge carriers are injected through the cathodes and anodes via bond pads 151 for recombination in the functional organic layers. The recombination of the charge carriers causes the functional layers of the cells to emit visible radiation.
FIG. 2 shows a section of the interconnection between the bond pads and external driving circuitry in conventional OLED devices. A flex connector 206 is bonded to the substrate 101 using, for example, an anisotropic conducting film (ACF) 208. The flex connector provides the external electrical interconnection from the device to the driving circuitry, which provides the current for driving the active components. A contact layer 150 is deposited on the substrate, and used to provide the electrical interconnection between the device and the flex connector. The contact layer comprises a metal such as Al, Au, Ag, Cu, Cr or Ni.
However, the contact layer is exposed to the environment at portions such as 210, and is highly susceptible to damage caused by reaction with atmospheric components such as oxygen and water. The flex connector may be de-bonded from the contact layer over time, degrading the reliability of the interconnection. Moreover, the contact layer exhibits poor adhesion to the substrate and ACF, leading to low reliability, difficult processing and higher production costs.
As evidenced from the foregoing discussion, it is desirable to provide an improved interconnection to increase the reliability and lifetime of a device.